Moisture-measuring instrument



Dec. 19, 1944. H W 2,365,496-

MOIS'I'URE MEASURING INSTRUMENT Filed 001:. 19, 1943 2 Sheets-Sheet 1 INVENTOR C.S.SHAW 1 ATTORNEYS Dec. 19, 1944.

c. s. SHAW MOISTURE MEASURING INSTRUMENT Filed Oct. 19, 1943 2 Sheets-Sheet 2 INVENTOR C.S.$HAW

ATTORNEYS Patented Dec. 19, 194 1 accuse morsrnanmzasonmo ms'mnmn'r les s. Shaw, a, assumito United States of America, as represented by the Secretory of Agriculture fiippiicutlcn (Pctober 19, 1943, Serial No. 506,835

This application is made under the act of March 3, 1883, as amended by the act of April 361?, i928}, and the invention herein described, if patented, may be manufactured and used by or tor the Government of the United States of [merit-3e, for goveentel purposes without the payment to me of any royalty thereon.

This invention relates to on instrument and or method for deteng the moisture content of resilient hygroscopic fibrous materials, such as lint cotton.

According to the customary laboratory practice, moisture content of a sample is determined by weighing the sample, drying, reweighing the dried sample, and computing the moisture content from the weights thus obtained. This invention eliminates the necessity for this tedious procedure, and hes omens its obiects the provision of a device for directly determining the moisture con-tent at n sample in e simple and expeditious manner; the provision of such a. device which is of simple construction, and which can be readily assembled and disassembled from a few easily obtained or concied parts; and the provision of a method for measuring the moisture content based on the property of coherent flufiy masses of filamentary hygroscopic fibrous organic materials, such as cotton fiber, of altering the degree of pressure exerted by the mass when in a compressed state, with variation of its absorbed moisture content.

When cotton fiber or a similar material is compressed, the pressure exerted by the material varies with its absorbed moisture content, the greater moisture content resulting in lesser pressure. present invention utilizes this phenomenon as the basis for measuring the absorbed moisture content oi a sample of such material, and in general comprises a device which will measwe the pressure exerted by the sample when pressure is applied to it while confined to unidirectional displacement, such measurement givme an index from which the absorbed moisture content can be determined directly.

In the following description of the invention,

' on the stand. A base-block, it having an aper" ture it is mounted on the top it with. its aperture in alignment with aperture it. A circular block ll provided with a central countersunk aperture it is mounted on the base-block with its aperture aligning with apertures it and it, and an upright, rigid well, metal cylinder it having an open end at its top and a polished inside surface is detachably mounted by means of clips to with its lower end surrounding the circular block, W.

A circular follow-block it, having substantially the same cross-sectional area as the inside of the cylinder, is mounted for free longitudinal movement inside the cylinder on a follow-block guide rod 22 extending downwardly through apertures 14, I6, and I8, and is movable downwardly against the action of a coil compression, spring 23 which surrounds the guide rod 22 and engages the followblock 2| and the circular block H at its upper and lower ends, respectively. The lower end of the spring is seated in the countersunk aperture l8.

The circular follow-block has indicator means movable therewith, such as a pointer 24 secured to the follow-block and projecting through a longitudinally extending slot 25 in the wall of cylinder 19 for traversing the pressure scale 28 secured adjacent to the slot. Thus, if 'a. sample is compressed against the follow-block 2'! within the cylinder, the pressure exerted by the sample will cause a compression of spring 23 and will be indicated by movement of pointer 24 on scale 26 giving an index of the moisture content of the sample. a

Means for applying pressure to the sample to compress it within the cylinder is also mounted on the stand by means of a support bracket having a vertical stud 30 and horizontal arm 3! positioned over the stand. A pressure-block 82, having substantially the same cross-sectional area as the inside of the cylinder and mounted to move downwardly into the open end or the cylinder, is attached to the lower end of a tail-rod 33 slidably mounted in a sleeve 84 carried by bracket 35 attached to the stud 30. The pressure-block and tail-rod are moved upwardly by tension spring 86 attaching the upper end of the tail-rod to horizontal arm 3| Downward movement of the pressure-block is imparted by a foot lever ill pivotally attached at one end the rear pair of supporting legs i2 oi the stand and with its other end in a convenient location to be moved by the operator. Tie cables 38 and 39 connect the lever through turn buckles iii and li to a cross-head 32 attached below the sleeve 3d to the tail-rod 83. A tension spring :33 attached between the foot lever and the stand top works in unison with tension spring normally to hold the foot-lever in its raised position.

The pressure-block is limited in itsupward and downward movement by crosshead G2, which serves as a stop to engage with sleeve 36 and the upper end of the cylinder l9, respectively.

In use, samples are placed in the cylinder as indicated at 65 (Figure 4), are compressed by downward movement of the foot lever until the crosshead strikes the top of the cylinder, and the movement of the follow-block and consequent pressure exerted by the sample are read on scale 26, the instrument being first calibrated. Calibration is accomplished by testing a number of known samples, each having a definite unit weight, of the same type material and of varying moisture contents, and by plotting on acalibration chart the readings from scale 26 against the moisture contents of the various samples.

To determine the moisture content of an unknown sample of the same type material, all that is necessary is to place the same definite unit weight of the material for which the instrument is calibrated into the cylinder, press the foot lever until the crossrod strikes the cylinder, take the scale reading, and by reference tothe calibration chart pick out the correct moisture content reading.

Of course, if the instrument is to be used for testing only one type of material, the moisture content calibrations can be written directly on scale 26, or for a few types they may be written side byside on the scale.

The embodiment illustrated in Figure 5 is similar in all details to that heretofore described,

except as to the scale, and only the modified aeoaeae ment gives an amplified reading of the scale; also, the position of the scale is more convenient for the operator to take the readings.

' Having thus described the invention, what is claimed is:

1. An. instrument for measuring the absorbed moisture content of a sample of resilient hygroscopic fibrous substance comprising: a stand, an upright rigid wall cylinder having an open top and mounted on the strand, a compression spring in the cylinder, a follow-block mounted within the cylinder in engagement with the spring and freely movable downwardly against its action, a pointer movable with the follow-block, a scale traversed by the pointer, a pressure-block mounted to move downwardly into the open end of the cylinder, said follow-block and pressure-block having substantially the same cross-sectional areas as the inside of the cylinder, a stop movable with the pressure-block and engaging the upper end of the cylinder to limit downward movement of the pressure block into the cylinder, and means for moving the pressureeblock into the cylinder to apply pressure to a definite unit weight of a sample of the. substance when placed in the cylinder on the ,follow-block, whereby the moisture content of the sample may be determined by comparing the pressure exerted by it when compressed to that of the same definite unit weight of a known moisture-content sample of a similar substance when compressed under like circumstances.

2. An instrument for measuring the absorbed moisture content of a sample of resilient hygroscopic fibrous substance comprising: an open-end. rigid wall cylinder, 9. follow-block mounted within the cylinder and freely movable away from the open end of the cylinder, a spring against which the follow-block is movable, a pressureblock movable into the open end of the cylinder a limited distance, said follow-block and pressureblock having substantially the same cross-sectional areas as the inside of the cylinder, whereby a sample of the substance may be placed in the cylinder and pressure applied to'it by movement of the pressure-block its limited distance and pressure of thesample will cause movement of the follow-block, a scale, and means movable with the follow-block and movable relative to the 

